Roadside Bluetooth, Wi-Fi Sensors Increase Traffic Flow

An Ontario transportation project represents a larger trend toward the use of Bluetooth and Wi-Fi sensors to speed up the flow of traffic.

As the cost of sensors drops and more vehicles become equipped with wireless capabilities, new opportunities arise for transportation agencies. The Ministry of Transportation for Ontario (MTO) announced on Nov. 13 the installation of combined Bluetooth and Wi-Fi sensors on one of its busiest highways, Queen Elizabeth Way, with the intent of better managing traffic flow.

The two devices provided by G4 Apps, a partner of BLIP Systems, cover eight lanes of traffic over about 12 miles. The devices anonymously collect Wi-Fi and Bluetooth signals transmitted by travelers’ smartphones or in-vehicle systems at two points on the road, calculating traffic speed and congestion. The system is being used by the MTO to help recalibrate the old algorithm used by existing in-ground induction loop sensors, which have been installed for about 15 years. The old algorithm wasn’t as accurate as the MTO wanted, said Bob Burrows, CEO of G4 Apps.

“For this particular instance, the Ministry of Transportation for Ontario is using it expressly for posting travel time to enable people to make decisions on which path to take between two highways to get to downtown Toronto,” Burrows said. An MTO study demonstrated about a 20 percent increase in traffic flow with the use of such sensors and signage indicating travel times for alternate routes.

The investment in sensor technology for traffic monitoring is worth it, Burrows said, especially considering the cost of the technology that it replaces. “The old system is easily $100,000 per kilometer, and they’ve covered 20 kilometers here for less than $10,000 using our technology,” he said, adding that installation is easier and faster than digging into the ground. “It took us an hour to get the units up, running and reporting.”

One issue with in-ground induction loops, Burrows said, is they can crack from frost and if the road isn’t scheduled for maintenance then the loop remains broken for months or years until the next round of maintenance. The benefits of sensor technology have recently attracted much interest around Canada, the U.S. and the world, he said.

BLIP Systems’ technology is installed in road networks around Denmark, Canada, the U.S., Germany, Sweden, Norway, New Zealand, Australia and Ireland. International airports and railway stations are also using the technology to manage the flow of people on foot through their facilities and to increase safety, Burrows said.

Burrows said Toronto is considering deploying such a system soon, both as an extension of the Queen Elizabeth Way rollout and inside the city, where sensors at every intersection will detect when traffic slows.

Calgary installed a similar Bluetooth monitoring system of about 30 devices designed by a BLIP Systems competitor. The Ministry of Transportation for Quebec is now piloting such a system for use around greater Montreal and inside Quebec City, Burrows said. In addition, Massachusetts and Pennsylvania also have installed similar technology in recent years.

Modern alternatives to Bluetooth and Wi-Fi sensors include radar, which is being used by the MTO to detect wildlife, but is capable of detecting vehicles as well. The downside to radar, Burrows said, is that it doesn’t calculate travel time because the technology doesn’t identify particular vehicles -- radar essentially just counts shapes going by.

Another alternative is automatic license plate recognition. Although such systems have a higher vehicle detection rate compared to the 20 to 30 percent rate attained by Bluetooth and Wi-Fi sensors, the technology is more expensive to implement on freeways. While a couple roadside Bluetooth and Wi-Fi devices can cover miles of eight-lane freeway, license plate recognition typically requires one device per lane.

One of the most common and important questions about Bluetooth and Wi-Fi roadside systems, Burrows said, is that of privacy. The Bluetooth and media access control addresses collected by the system are anonymous to begin with, Burrows said, and on top of that the data is hashed in the device before being sent to the central server. It’s anonymous and untraceable, he said.

Privacy issues aside, technology like this will become more common, Burrows said. “It’s always hard to get them to make a change, but it’s going to come eventually,” he said. “As we start seeing more of those sensors in cars, that dramatically sends up the volume and lowers the cost. I think at some point we’ll see some automotive-grade sensors coming into use for traffic monitoring as well.”